Early detection of plant health is crucial for ensuring crop health, optimizing yields, and supporting sustainable agricultural practices. The timely identification of stress factors is enabled through spectral imaging, which has emerged as a powerful, non-invasive tool for monitoring plant stress responses. This thesis investigates the integration of spectral imaging and machine learning techniques for detecting various stressors in potato plants, utilizing multispectral and hyperspectral data collected under both controlled and field conditions. To enhance stress detection accuracy and interpretability, advanced modeling approaches were employed, including deep neural networks, boosting models, and explainability techniques. Feature selection methods were further applied to identify key spectral wavelengths associated with specific stress responses, contributing to a deeper understanding of plant physiological changes under varying stress conditions. The results demonstrate that machine learning models can effectively differentiate between healthy and stressed plants, even before visible symptoms appear. Notably, these models achieved an F1 score of up to 0.95 for identifying water-stressed plants, 100% reliability in detecting nematode-infested potato plants and tubers, and an F1 score of 0.826 for detection of early blight infections. However, the findings also highlight the challenges of distinguishing between biotic and abiotic stressors, particularly in cases of concurrent stress factors. The analysis identified key spectral bands for stress detection: 475–580 nm, 660–730 nm, 940–970 nm, 1420–1510 nm, 1875–2040 nm, and 2350–2480 nm (water stress in potato plants). The near-infrared part of the spectrum was identified as significant for early blight detection, followed by blue and green bands. Additionally, 1000–1200 nm was linked to the insides of nematode-infested tubers, while 1500–1600 nm, 1850–2000 nm, and 2300–2450 nm corresponded to their outsides. These findings provide valuable insights into plant physiology and have significant implications for precision agriculture, offering advancements in disease detection. By integrating spectral imaging with artificial intelligence, this research contributes to the development of innovative tools for mitigating the challenges posed by climate change and plant pests and diseases.
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